Acquiring the parts for the Duckiebot

Jacopo

The trip begins with acquiring the parts. Here, we provide a link to all bits and pieces that are needed to build a Duckiebot, along with their price tag.

In general, keep in mind that:

  • The links might expire, or the prices might vary.
  • In general, substitutions are OK for the mechanical components, and not OK for all the electronics, unless you are OK in writing some software.

Resources necessaries:

  • Cost: USD ???
  • Time: ??? days (average shipping)

Results:

  • A kit of parts ready to be assembled.

Duckiebot configurations

Configuration D17-0: Only camera and motors.

Configuration D17-0+w: Previous one + an additional WiFi card (Edimax).

Configuration D17-1: LED lights and bumpers

Bill of materials

Chassis

We selected the Magician Chassis as the basic chassis for the robot (Figure 1).

We chose it because it has a double-decker configuration, and so we can put the battery in the lower part.

The chassis pack includes the motors and wheels as well as the structural part.

The price for this in the US is about USD 15-30.

The Magician Chassis

Raspberry PI 3 (RPI-3)

The RPI-3 is the central computer of the Duckiebot. Duckiebot version D17 uses Model B (Figure 2) (A1.2GHz 64-bit quad-core ARMv8 CPU, 1GB RAM), a small but powerful computer.

The Raspberry PI 3 Model B

The price for this in the US is about USD 35.

Power Supply

We want a hard-wired power source (5VDC, 2.4A, Micro USB) to suppply the RPI-3 (Figure 3).

The Power Supply

The price for this in the US is about USD 5-10.

Heat Sinks

The RPI-3 will heat up significantly during use. It is warmly recommended to add heat sinks, as in Figure 4. Since we will be stacking HATs on top of the RPI-3 with 15 mm standoffs, the maximum height of the heat sinks should be well below 15 mm. The chip dimensions are 15x15 mm and 10x10 mm.

The Heat Sinks

Class 10 MicroSD Card

The MicroSD card Figure 5is the hard disk of the RPI-3. 16 GigaBytes of capacity are sufficient.

The MicroSD card

Camera

The Camera is the main sensor of the Duckiebot. Version D17 equips a 5 Mega Pixels 1080p camera with wide field of view ($160^\circ$) fisheye lens (Figure 6).

The Camera with Fisheye Lens

Camera Mount

The camera mount (Figure 7) serves to keep the camera looking forward at the right angle to the road (looking slightly down). The front cover is not essential.

The Camera Mount

300mm Camera Cable

A longer (300 mm) camera cable Figure 8 make assembling the Duckiebot easier, allowing for more freedom in the relative positioning of camera and computational stack.

A 300 mm camera cable for the RPI-3

Wifi Augmenter

The Edimax AC1200 EW-7822ULC wifi adpater Figure 9 improves the interactions with the Duckiebot by improving the connectivity between Duckiebot and laptop, especially useful in crowded environments (e.g., classroom).

The Edimax AC1200 EW-7822ULC wifi adapter

Joypad

The joypad is used to manually remote control the Duckiebot. Any 2.4 GHz wireless controller (with a tiny USB dongle) will do.

The model link in the table (Figure 10) does not include batteries (2 AA 1.5V)!

A Wireless Joypad

DC Stepper Motor HAT - Mini Kit

We use the DC+Stepper motor HAT to control the motors that drive the wheels.

The Stepper Motor HAT

Male-Male Jumper Wires

Premier Male-Male Jumper Wires

GPIO Stacking Headers

The Stacking Headers

16-Channel PWM/Servo HAT for Raspberry Pi - Mini Kit

The PWM-Servo HAT

Battery

The battery provides power to the Duckiebot.

We choose this (Figure 15) battery because it has a good combination of size (to fit in the lower deck of the Magician Chassis), high output amperage (2.4A and 2.1A at 5V DC) over two USB outputs, a good capacity (10400 mAh) at an affordable price (USD 20).

The Battery

Standoffs, Nuts and Screws

We use non electrically conductive standoffs (M2.5 12mm F 6mm M), nuts (M2.5), and screws (M2.5x10mm) to hold the RPI-3 to the chassis and the HATs stacked on top of the RPI-3.

In versions D17-0 and D17-0+w, the Duckiebot requires 12 standoffs, 4 nuts and 4 screws.

In version D17-1, the Duckiebot requires 16 standoffs, 4 nuts and 4 screws.

Standoffs, Nuts and Screws

Ziptie

Two long (300x5 mm) zipties are going to be useful to keep the battery at the lower deck from moving around.

The Zipties

LEDs

In the fancy version D17-1, the Duckiebot is equipped with 5 RGB LEDs. LEDs can be used to signal to other Duckiebots, or just make cool patterns!

The pack of LEDs linked in the table above holds 10 LEDs, enough for two Duckiebots.

The RGB LEDs

LED HAT

Daughterboard for Adafruit 16-Channel PWM / Servo HAT that enables connection with RGB LEDs, ADS1015 12 Bit, 4 Channel ADC, Monochrome 128x32 I2C OLED graphic display, and Adafruit 9-DOF IMU Breakout - L3GD20H + LSM303.

The LED HAT

Female-Female Jumper Wires

Premier Female-Female Jumper Wires

Bumpers

The Bumpers

Passive Electric Components

Because of mathjax bug
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